Water is the one thing we cannot go without, wherever we go. Whether you're drinking tap water from the hotel you're staying at, or from a natural source nearby your campsite, you need to make sure that it's not contaminated.

One sip of the “wrong” water, and you may end up with E.coli, hepatitis – and who knows what other diseases.

Regardless of the source, ensuring the water you drink is safe is vital. You may test it, you may treat it – you may do both. The end result should be that you drink clean water that doesn't make you ill.

But how can you be sure?